Chevrolet Repair: Vacuum leak, chevy astro van, intake manifold gasket

Question
I have a Chevy Astro Van 91 and it seems to be missing in idle and when you turn on the air it does not blow through the top vents. So I think I have a vacuum leak.

Answer
Hello Johnny,
Sounds like it to me also.
There is the obvious possibility of the hoses, and vacuum storage canister leaking.
Then there is the brake booster.
Then there is the EGR valve could be stuck open.
And there could also be a leak in the intake manifold gasket.
See if you can get a vacuum guage and connect it to the manifold, and see what it shows.

Van